Synthesis of Information Related to Highway Practices. Topic 53-11. Resilient Design with Distributed Rainfall Modeling

According to the National Oceanic and Atmospheric Administration, the number and cost of weather and climate-related disasters are increasing in the United States due to a combination of increased exposure, vulnerability, and the fact that climate change is increasing the frequency of extreme events. The increased frequency of hurricanes and severe storm events are requiring state departments of transportation (DOTs) to consider how to anticipate, plan for, and adapt to these changing conditions. In addition, state DOTs are considering how to withstand, respond to, and recover more rapidly when disruptions occur. For this reason, conventional methods of hydrologic analysis are being supplemented by more complex hydrologic modeling that allows for scenario testing and impact assessment. Distributed rainfall methods are empirical models that use physical equations to describe rainfall patterns and water movement to create flow rates. Distributed rainfall models are unique among hydrologic models, in that they have more detailed methods of tracking runoff accumulation. These models split the watershed into small elements that are used to calculate and track infiltration and movement of runoff on the ground by using empirical equations and simplified momentum equations. In comparison, statistical methods do not explicitly track accumulation and empirical methods such as the Natural Resources Conservation Service methods and have simpler methods of tracking water accumulation that only use a few locations within the watershed. Historically, these distributed rainfall models have been used mostly in research settings for two main reasons: (1) they can have a higher level of accuracy and complexity due to the more detailed physics modeling, and (2) they are computationally expensive because they are solving the water movement in many locations within the watershed. Increased computing power and modeling efficiency have made distributed rainfall models more cost effective for mid-level to simple engineering projects. Because distributed models are empirical, they also have more flexibility than statistical methods because they are not linked to gauge data within a specific region. As a result, there has been an upsurge in popularity among engineering practitioners using distributed rainfall models to create more resilient designs. However, there has been little documented guidance on applying distributed rainfall models to help engineers use them in the highway design process. The objective of this synthesis is to document state DOT uses of distributed rainfall models. The synthesis will focus on the use of distributed rainfall methods for hydrologic analyses of bridge projects and highways in floodplains.


  • English


  • Status: Proposed
  • Funding: $45000
  • Contract Numbers:

    Project 20-05, Topic 53-11

  • Sponsor Organizations:

    National Cooperative Highway Research Program (NCHRP) Synthesis

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Gause, Jo

  • Start Date: 20210430
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01771600
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic 53-11
  • Files: TRB, RIP
  • Created Date: May 17 2021 3:14PM